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jimmy comments on What Are Probabilities, Anyway? - Less Wrong

24 Post author: Wei_Dai 11 December 2009 12:25AM

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Comment author: jimmy 16 December 2009 05:08:32AM *  0 points [-]

There are possible worlds that are pretty good approximations to popular religions.


I don't understand this...

The paper does a much more thorough job than I, but the summary is that the only consistent way to carve is into borne probabilities, so you have to weight branches accordingly. I think this has to due with the amplitude squared being conserved, so that the ebborians equivalent would be their thickness, but I admit some confusion here.

This means there's at least some sense of probability in which you don't get to 'wish away', though it's still possible to only care about worlds where "X" is true (though in general you actually do care about the other worlds)

Comment deleted 16 December 2009 08:49:17AM [-]
Comment author: jimmy 16 December 2009 06:58:09PM 0 points [-]

It means that if you are in one, probability does not come down to only preferences. I suppose that since you can never be absolutely sure you're in one, you still have to find out your weightings between worlds where there might be nothing but preferences.

The other point is that I seriously doubt there's anything built into you that makes you not care about possible worlds where QM is true, so even if it does come down to 'mere preferences', you can still make mistakes.

The existence of an objective weighting scheme within one set of possible worlds gives me some hope of an objective weighting between all possible worlds, but note all that much, and it's not clear to me what that would be. Maybe the set of all possible worlds is countable, and each world is weighted equally?

Comment deleted 17 December 2009 08:20:04AM [-]
Comment author: jimmy 17 December 2009 10:59:03PM 0 points [-]

Yeah, but the confusion gets better as the worlds become more similar. How to weight between QM worlds and nonQM worlds is something I haven't even seen an attempt to explain, but how to weight within QM worlds has been explained, and how to weight in the sleeping beauty problem is quite straight forward.

I meant countable, but now that you mention it I think I should have said finite- I'll have to think about this some more.